JPH09257575A - Light frequency synchronous type detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove influence of flickering, and perform highly accurate sampling by sampling output of a light sensor in the timing of a sampling waveform in synchronism with an AC frequency measured by a frequency detecting circuit. SOLUTION: An Ac frequency of an AC power source 1 is measured by a frequency detecting circuit 4 connected to the AC power source (a commercial AC power source) 1, and a reference waveform of sampling is formed from the measured AC frequency by a waveform forming circuit 6. A sampling circuit 5 samples output of a light sensor 3 in the timing of this reference waveform. In this case, output of the light sensor 3 shows a waveform changing in a flickering frequency of a light source (a fluorescent lamp) 2, and since the reference waveform of sampling is the same frequency as flickering, when sapling is performed on output of the light sensor in the timing of this sampling waveform, output of a smooth output waveform can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical frequency synchronization type detection device used when detecting the presence / absence of an object, speed, etc. by using an optical sensor.

[0002]

2. Description of the Related Art Conventionally, a fluorescent lamp is one of the most commonly used indoor lighting fixtures. The light emitted from the fluorescent lamp blinks at the frequency of the alternating current from the mechanism. Is repeated. Usually, this blinking is not perceived by the naked eye, but an optical sensor (detector) that responds at high speed may detect the flicker, which may affect the detection data.

[0003]

In the prior art, when measuring flicker light such as a fluorescent lamp with an optical sensor such as a photodiode, the output light of the optical sensor flickers when the response of the optical sensor is fast. When the data is collected by sampling (information data collection) at regular intervals with this output signal,
Depending on the sampling timing (time zone), the output value shows a value that fluctuates extremely.

Particularly, this phenomenon may cause trouble when it is necessary to measure a relatively high-speed increase / decrease of the light quantity by a photosensor in an environment such as a room where a fluorescent lamp is used as a light source. A solution was needed.

According to the present invention, when sensing (detection) is performed by a photosensor in an environment under a light source having flicker, the output waveform having the frequency of flicker is sampled at an appropriate sampling frequency so as to flicker. It is an object of the present invention to provide an optical frequency synchronization type detection device capable of avoiding the influence of the above.

[0006]

An optical frequency synchronization type detection device of the present invention comprises an optical sensor for detecting a change in intensity of a light source irradiated by an AC power supply, and a frequency detection circuit for measuring the frequency of the AC power supply. A waveform generation circuit that generates a sampling waveform that is synchronized with the AC frequency measured by the frequency detection circuit, and a sampling circuit that samples the output of the optical sensor based on the sampling waveform are featured.

The optical frequency synchronization type detector according to the second aspect is characterized in that the absolute value of the AC voltage obtained from the AC power source is sampled at a time equal to a preset AC power source voltage set value.

The optical frequency-synchronous detection device according to a third aspect of the invention is an optical sensor for detecting a change in intensity of a light source irradiated by an AC power source, and a flicker of the light source due to an output signal output from the optical sensor. A frequency detection circuit that measures the frequency of the signal, a waveform generation circuit that generates a sampling waveform that is synchronized with the flickering frequency measured by the frequency detection circuit, and a sampling circuit that samples the output signal based on the sampling waveform. It is characterized by that.

Further, the optical frequency synchronization type detection device according to a fourth aspect is characterized in that the output voltage value of the optical sensor is sampled at a time equal to a predetermined optical sensor output voltage set value.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of an optical frequency synchronization type detection device of the present invention will be described. In FIG. 1, an optical sensor 3 is a device for detecting a change in the intensity of a light source 2 irradiated by an AC power supply 1, and a frequency detection circuit 4 is an AC power supply 1
Is a circuit which is connected to and measures the frequency of the AC power supply 1.

The waveform generation circuit 6 is connected to the frequency detection circuit 4 and generates a sampling waveform B shown in FIG. 2 from the AC frequency measured by the frequency detection circuit 4. The sampling circuit 5 includes the waveform generation circuit 6 and This circuit is connected to the optical sensor 3 and samples the optical sensor output A output from the optical sensor 3 based on the sampling waveform B output from the waveform generation circuit 6 to output an output value C.

That is, this embodiment is used when the frequency of flicker is known, such as a fluorescent lamp, and is composed of a light source 2, a frequency detection circuit 4, an optical sensor 3, a sampling circuit 5 and a waveform generation circuit 6. The light source 2 is a fluorescent lamp which is supplied with power from a commercial AC power source. The optical sensor 3 has a function of converting the received light beam of the light source 2 into an electric current,
The frequency detection circuit 4 detects the frequency of the alternating current used as the power source from the commercial AC power source.

Further, the waveform generation circuit 6 generates a sampling reference waveform from the detected AC frequency, the sampling circuit 5 performs sampling with this reference waveform, and outputs a sampled signal.

With this configuration, as shown in FIG. 2, there is a relationship between the optical sensor output A, the sampling waveform B, and the output value C, and the optical sensor output A shows a waveform that fluctuates at the frequency of flicker of the light source. The sampling waveform B has the same frequency as the flicker frequency.
When the optical sensor output A is sampled at the timing of, the output value C having a smooth output waveform shown below can be obtained.

FIG. 5 is an explanatory view for explaining the operation of the optical frequency synchronization type detector according to the second aspect of the present invention, in which the absolute value of the AC voltage D obtained from the AC power supply is the predetermined AC power supply voltage set value V. It is characterized by sampling at the same time.

That is, the light source 2 is a fluorescent lamp supplied with electric power from a commercial AC power source, and the optical sensor 3 converts the received light beam of the light source 2 into an electric current. The frequency detection circuit 4 detects the frequency of the alternating current used as the power source from the commercial AC power source, and the waveform generation circuit 6 generates the reference waveform for sampling at the time when the absolute values of the voltage values are equal, from the detected alternating voltage. .
The sampling circuit 5 performs sampling with this reference waveform and outputs the sampled signal.

FIG. 5 shows the photosensor output A, the AC voltage D, the sampling waveform B, and the output value C. The optical sensor output A shows a waveform that fluctuates at the flickering frequency of the light source 2. The sampling waveform B generates a reference waveform for sampling at times when the absolute values of voltage values are equal. When the optical sensor output A is sampled at the timing of this sampling waveform B, an output value C having a smooth output waveform shown below can be obtained. By applying this method,
This enables faster sampling than in the case of.

FIG. 3 shows an embodiment of the optical frequency synchronization type detection device according to the third aspect of the present invention, in which an optical sensor 3 for detecting a change in the intensity of the light source 2 irradiated by the AC power source 1 and an optical sensor 3 are detected. A frequency detection circuit 4 for measuring the flicker frequency of the light source based on the output signal output from the light source; a waveform generation circuit 6 for generating a sampling waveform B shown in FIG. 4 from the flicker frequency measured by the frequency detection circuit 4; And a sampling circuit 5 for sampling the optical sensor output A based on the waveform B and outputting the output value C.

That is, this optical frequency synchronization type detection device is applied to the case where the flicker of the light source 2 is unknown, and is composed of the optical sensor 3, the sampling circuit 5, the waveform generation circuit 6 and the frequency detection circuit 4. Then, the optical sensor 3 is the light source 2
The light beam from the sensor is received, converted into an electric current, and output. The frequency detection circuit 4 detects the flicker frequency from the signal from the optical sensor 3, and the waveform generation circuit 6 generates a sampling reference waveform based on the frequency. Then, the sampling circuit 5 performs sampling with this reference waveform and outputs the sampled signal.

FIG. 4 shows the optical sensor output A, the sampling waveform B, and the output value C. The optical sensor output A shows a waveform that fluctuates at the flicker frequency of the light source 2, and the sampling waveform B has the same frequency as the flicker frequency. When the optical sensor output is sampled at the timing of this sampling waveform B, it is shown below. Output value C of smooth output waveform
Can be obtained.

Further, FIG. 6 is an explanatory view for explaining the operation of the optical frequency synchronization type detection device described in claim 4, and the optical sensor output A is sampled at a time equal to a predetermined optical sensor output voltage set value. It is characterized by that.

That is, the optical sensor 3 receives the light beam from the light source 2, converts it into an electric current, and outputs it. The frequency detection circuit 4 detects the flicker frequency from the signal from the optical sensor 3, and the waveform generation circuit 6 A reference waveform for sampling is generated at a time when the voltage values of the output voltage of the optical sensor used as a reference during sampling are equal. The sampling circuit performs sampling with this reference waveform and outputs the sampled signal.

FIG. 6 shows the optical sensor output A, the sampling waveform B, and the output value C. The optical sensor output A shows a waveform that fluctuates at the flicker frequency of the light source 2, and the sampling waveform B
Indicates a reference waveform for sampling at a time when the reference AC voltage or the voltage value of the optical sensor output voltage is equal. When the optical sensor output A is sampled at the timing of this sampling waveform B, an output value C having a smooth output waveform shown below can be obtained. By using this method, it is possible to perform sampling at a higher speed than that of FIG.

[0024]

According to the present invention, the accuracy of the optical frequency synchronization type detection device can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an optical frequency synchronization type detection device showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the operation of FIG.

FIG. 3 is a configuration diagram of an optical frequency synchronization type detection device showing an embodiment of claim 3;

FIG. 4 is an explanatory diagram showing the operation of FIG. 3;

FIG. 5 is an explanatory diagram showing an operation of claim 2.

FIG. 6 is an explanatory diagram showing an operation of claim 4;

[Explanation of symbols]

 1 AC power supply 2 Light source 3 Optical sensor 4 Frequency detection circuit 5 Sampling circuit 6 Waveform generation circuit

Claims (4)

[Claims] 1. An optical sensor for detecting a change in intensity of a light source irradiated by an AC power source, a frequency detection circuit for measuring the frequency of the AC power source, and a frequency detection circuit synchronized with the AC frequency measured by the frequency detection circuit. An optical frequency synchronization type detection device comprising: a waveform generation circuit that generates a sampling waveform; and a sampling circuit that samples the output of the optical sensor based on the sampling waveform. 2. The optical frequency synchronous detection device according to claim 1, wherein sampling is performed at a time when the absolute value of the AC voltage obtained from the AC power supply is equal to a predetermined AC power supply voltage set value. 3. An optical sensor for detecting a change in intensity of a light source irradiated by an AC power source, a frequency detection circuit for measuring a flicker frequency of the light source by an output signal output from the optical sensor, and this frequency. Optical frequency synchronization type detection device comprising: a waveform generation circuit that generates a sampling waveform that is synchronized with the fluctuating frequency measured by the detection circuit; and a sampling circuit that samples the output signal based on the sampling waveform. . 4. The optical frequency synchronous detection device according to claim 3, wherein sampling is performed at a time when the output voltage value of the optical sensor is equal to a predetermined optical sensor output voltage set value.